Hello all,
I have at my disposal stereo wave files of binaural recordings, ie recordings
for which the left channel corresponds to the signal perceived by the left ear,
and the right channel to the right ear.
I have made a small program that compute the rms amplitude of each channel and
takes the ratio, because my recordings have a constant amplitude I figured it
would be close to an Intensity difference...
But I am starting to have doubts, I don't think it makes sense...
How would you proceed to calculate these ILDs with just that wave file?
I am quite confused
Thanks for your help
Nicolas
Calculate Interaural Level Difference from a (stereo) sound file
Started by ●March 2, 2009
Reply by ●March 3, 20092009-03-03
Hei,
What does ILDs stand for? Do you mean interaural intensity difference?
Thanks
AC
-----ԭ-----
: a... [mailto:audiodsp] s...@worldonline.fr
ʱ 200932 3:28
: a...
: [audiodsp] Calculate Interaural Level Difference from a (stereo) sound file
Hello all,
I have at my disposal stereo wave files of binaural recordings, ie recordings for which the left channel corresponds to the signal perceived by the left ear, and the right channel to the right ear.
I have made a small program that compute the rms amplitude of each channel and takes the ratio, because my recordings have a constant amplitude I figured it would be close to an Intensity difference...
But I am starting to have doubts, I don't think it makes sense...
How would you proceed to calculate these ILDs with just that wave file?
I am quite confused
Thanks for your help
Nicolas
_____________________________________
What does ILDs stand for? Do you mean interaural intensity difference?
Thanks
AC
-----ԭ-----
: a... [mailto:audiodsp] s...@worldonline.fr
ʱ 200932 3:28
: a...
: [audiodsp] Calculate Interaural Level Difference from a (stereo) sound file
Hello all,
I have at my disposal stereo wave files of binaural recordings, ie recordings for which the left channel corresponds to the signal perceived by the left ear, and the right channel to the right ear.
I have made a small program that compute the rms amplitude of each channel and takes the ratio, because my recordings have a constant amplitude I figured it would be close to an Intensity difference...
But I am starting to have doubts, I don't think it makes sense...
How would you proceed to calculate these ILDs with just that wave file?
I am quite confused
Thanks for your help
Nicolas
_____________________________________
Reply by ●March 3, 20092009-03-03
Hello Nicolas,
Have you considered a coherence measurement? I'd have to look up the
formula, but it takes phase into account. Someone can probably correct
me but, IIRC, coherence doesn't give a result in absolute time but
rather in a number from 1 (positive phase/polarity) to -1 (negative
polarity), with zero meaning the signals have either no perceivable
relation or exact 90-degrees phase relation.
If your file includes sine waves of a known frequency, it might be
possible to then determine a time delay. If nothing else, a coherence
measurement is a useful tool to have at your disposal.
David
On Mon Mar 2, 2009 9:43 am ((PST)) "s...@worldonline.fr" s...@worldonline.fr
wrote:
>
> Hello all,
>
> I have at my disposal stereo wave files of binaural recordings, ie
> recordings for which the left channel corresponds to the signal
> perceived by the left ear, and the right channel to the right ear.
>
> I have made a small program that compute the rms amplitude of each
> channel and takes the ratio, because my recordings have a constant
> amplitude I figured it would be close to an Intensity difference...
>
> But I am starting to have doubts, I don't think it makes sense...
>
> How would you proceed to calculate these ILDs with just that wave
> file?
> I am quite confused
> Thanks for your help
>
> Nicolas
Have you considered a coherence measurement? I'd have to look up the
formula, but it takes phase into account. Someone can probably correct
me but, IIRC, coherence doesn't give a result in absolute time but
rather in a number from 1 (positive phase/polarity) to -1 (negative
polarity), with zero meaning the signals have either no perceivable
relation or exact 90-degrees phase relation.
If your file includes sine waves of a known frequency, it might be
possible to then determine a time delay. If nothing else, a coherence
measurement is a useful tool to have at your disposal.
David
On Mon Mar 2, 2009 9:43 am ((PST)) "s...@worldonline.fr" s...@worldonline.fr
wrote:
>
> Hello all,
>
> I have at my disposal stereo wave files of binaural recordings, ie
> recordings for which the left channel corresponds to the signal
> perceived by the left ear, and the right channel to the right ear.
>
> I have made a small program that compute the rms amplitude of each
> channel and takes the ratio, because my recordings have a constant
> amplitude I figured it would be close to an Intensity difference...
>
> But I am starting to have doubts, I don't think it makes sense...
>
> How would you proceed to calculate these ILDs with just that wave
> file?
> I am quite confused
> Thanks for your help
>
> Nicolas
Reply by ●March 3, 20092009-03-03
Hello David,
No, unit coherence means that the signals are linearly related at the
frequency values where it occurs.
Miguel
David Reaves wrote:
> Hello Nicolas,
> Have you considered a coherence measurement? I'd have to look up the
> formula, but it takes phase into account. Someone can probably correct
> me but, IIRC, coherence doesn't give a result in absolute time but
> rather in a number from 1 (positive phase/polarity) to -1 (negative
> polarity), with zero meaning the signals have either no perceivable
> relation or exact 90-degrees phase relation.
>
> If your file includes sine waves of a known frequency, it might be
> possible to then determine a time delay. If nothing else, a coherence
> measurement is a useful tool to have at your disposal.
>
> David
> On Mon Mar 2, 2009 9:43 am ((PST)) "s...@worldonline.fr" s...@worldonline.fr
> wrote:
>> Hello all,
>>
>> I have at my disposal stereo wave files of binaural recordings, ie
>> recordings for which the left channel corresponds to the signal
>> perceived by the left ear, and the right channel to the right ear.
>>
>> I have made a small program that compute the rms amplitude of each
>> channel and takes the ratio, because my recordings have a constant
>> amplitude I figured it would be close to an Intensity difference...
>>
>> But I am starting to have doubts, I don't think it makes sense...
>>
>> How would you proceed to calculate these ILDs with just that wave
>> file?
>> I am quite confused
>> Thanks for your help
>>
>> Nicolas
>
No, unit coherence means that the signals are linearly related at the
frequency values where it occurs.
Miguel
David Reaves wrote:
> Hello Nicolas,
> Have you considered a coherence measurement? I'd have to look up the
> formula, but it takes phase into account. Someone can probably correct
> me but, IIRC, coherence doesn't give a result in absolute time but
> rather in a number from 1 (positive phase/polarity) to -1 (negative
> polarity), with zero meaning the signals have either no perceivable
> relation or exact 90-degrees phase relation.
>
> If your file includes sine waves of a known frequency, it might be
> possible to then determine a time delay. If nothing else, a coherence
> measurement is a useful tool to have at your disposal.
>
> David
> On Mon Mar 2, 2009 9:43 am ((PST)) "s...@worldonline.fr" s...@worldonline.fr
> wrote:
>> Hello all,
>>
>> I have at my disposal stereo wave files of binaural recordings, ie
>> recordings for which the left channel corresponds to the signal
>> perceived by the left ear, and the right channel to the right ear.
>>
>> I have made a small program that compute the rms amplitude of each
>> channel and takes the ratio, because my recordings have a constant
>> amplitude I figured it would be close to an Intensity difference...
>>
>> But I am starting to have doubts, I don't think it makes sense...
>>
>> How would you proceed to calculate these ILDs with just that wave
>> file?
>> I am quite confused
>> Thanks for your help
>>
>> Nicolas
>
Reply by ●March 3, 20092009-03-03
Hi Nicolas,
According to what I have read so far, if you want to measure ILDs or
ITDs you need to split the signals into various number of bands (may
be 32) before you take the difference, else they wont make any
difference. You could use the QMF filters to divide the signals into
various frequency bands.
Vishwanath
On 3/3/09, David Reaves wrote:
> Hello Nicolas,
> Have you considered a coherence measurement? I'd have to look up the
> formula, but it takes phase into account. Someone can probably correct
> me but, IIRC, coherence doesn't give a result in absolute time but
> rather in a number from 1 (positive phase/polarity) to -1 (negative
> polarity), with zero meaning the signals have either no perceivable
> relation or exact 90-degrees phase relation.
>
> If your file includes sine waves of a known frequency, it might be
> possible to then determine a time delay. If nothing else, a coherence
> measurement is a useful tool to have at your disposal.
>
> David
> On Mon Mar 2, 2009 9:43 am ((PST)) "s...@worldonline.fr"
> s...@worldonline.fr
> wrote:
>>
>> Hello all,
>>
>> I have at my disposal stereo wave files of binaural recordings, ie
>> recordings for which the left channel corresponds to the signal
>> perceived by the left ear, and the right channel to the right ear.
>>
>> I have made a small program that compute the rms amplitude of each
>> channel and takes the ratio, because my recordings have a constant
>> amplitude I figured it would be close to an Intensity difference...
>>
>> But I am starting to have doubts, I don't think it makes sense...
>>
>> How would you proceed to calculate these ILDs with just that wave
>> file?
>> I am quite confused
>> Thanks for your help
>>
>> Nicolas
According to what I have read so far, if you want to measure ILDs or
ITDs you need to split the signals into various number of bands (may
be 32) before you take the difference, else they wont make any
difference. You could use the QMF filters to divide the signals into
various frequency bands.
Vishwanath
On 3/3/09, David Reaves wrote:
> Hello Nicolas,
> Have you considered a coherence measurement? I'd have to look up the
> formula, but it takes phase into account. Someone can probably correct
> me but, IIRC, coherence doesn't give a result in absolute time but
> rather in a number from 1 (positive phase/polarity) to -1 (negative
> polarity), with zero meaning the signals have either no perceivable
> relation or exact 90-degrees phase relation.
>
> If your file includes sine waves of a known frequency, it might be
> possible to then determine a time delay. If nothing else, a coherence
> measurement is a useful tool to have at your disposal.
>
> David
> On Mon Mar 2, 2009 9:43 am ((PST)) "s...@worldonline.fr"
> s...@worldonline.fr
> wrote:
>>
>> Hello all,
>>
>> I have at my disposal stereo wave files of binaural recordings, ie
>> recordings for which the left channel corresponds to the signal
>> perceived by the left ear, and the right channel to the right ear.
>>
>> I have made a small program that compute the rms amplitude of each
>> channel and takes the ratio, because my recordings have a constant
>> amplitude I figured it would be close to an Intensity difference...
>>
>> But I am starting to have doubts, I don't think it makes sense...
>>
>> How would you proceed to calculate these ILDs with just that wave
>> file?
>> I am quite confused
>> Thanks for your help
>>
>> Nicolas
Reply by ●March 5, 20092009-03-05
I am not familiar with the term "unit coherence." From what I recall,
correlation and coherence are not the same thing.
IIRC, correlation alone indicates whether signals are identical but
infers no timing information, whereas perfect ("+1") coherence means
that two signals are correlated AND time/phase-matched.
But I may be wrong, and would be very interested to see a reference.
I'm not sure where level difference fits into the picture.
For example, a while back, after having used a coherence meter as part
of an audio measurement package, I set out to model a coherence
detector in DSP, and was amazed that it was possible to get an
accurate measurement even when the signals were many dB different in
level.
David
On Tue Mar 3, 2009 6:08 pm ((PST)) "Miguel Arjona Ramez" wrote:
>
> Hello David,
>
> No, unit coherence means that the signals are linearly related at the
> frequency values where it occurs.
>
> Miguel
>
> David Reaves wrote:
>> Hello Nicolas,
>> Have you considered a coherence measurement? I'd have to look up the
>> formula, but it takes phase into account. Someone can probably
>> correct
>> me but, IIRC, coherence doesn't give a result in absolute time but
>> rather in a number from 1 (positive phase/polarity) to -1 (negative
>> polarity), with zero meaning the signals have either no perceivable
>> relation or exact 90-degrees phase relation.
>>
>> If your file includes sine waves of a known frequency, it might be
>> possible to then determine a time delay. If nothing else, a coherence
>> measurement is a useful tool to have at your disposal.
>>
>> David
>> On Mon Mar 2, 2009 9:43 am ((PST)) "s...@worldonline.fr" skeid@worldonline.fr
>> wrote:
>>> Hello all,
>>>
>>> I have at my disposal stereo wave files of binaural recordings, ie
>>> recordings for which the left channel corresponds to the signal
>>> perceived by the left ear, and the right channel to the right ear.
>>>
>>> I have made a small program that compute the rms amplitude of each
>>> channel and takes the ratio, because my recordings have a constant
>>> amplitude I figured it would be close to an Intensity difference...
>>>
>>> But I am starting to have doubts, I don't think it makes sense...
>>>
>>> How would you proceed to calculate these ILDs with just that wave
>>> file?
>>>
>>>
>>> I am quite confused
>>> Thanks for your help
>>>
>>> Nicolas
>
_____________________________________
correlation and coherence are not the same thing.
IIRC, correlation alone indicates whether signals are identical but
infers no timing information, whereas perfect ("+1") coherence means
that two signals are correlated AND time/phase-matched.
But I may be wrong, and would be very interested to see a reference.
I'm not sure where level difference fits into the picture.
For example, a while back, after having used a coherence meter as part
of an audio measurement package, I set out to model a coherence
detector in DSP, and was amazed that it was possible to get an
accurate measurement even when the signals were many dB different in
level.
David
On Tue Mar 3, 2009 6:08 pm ((PST)) "Miguel Arjona Ramez" wrote:
>
> Hello David,
>
> No, unit coherence means that the signals are linearly related at the
> frequency values where it occurs.
>
> Miguel
>
> David Reaves wrote:
>> Hello Nicolas,
>> Have you considered a coherence measurement? I'd have to look up the
>> formula, but it takes phase into account. Someone can probably
>> correct
>> me but, IIRC, coherence doesn't give a result in absolute time but
>> rather in a number from 1 (positive phase/polarity) to -1 (negative
>> polarity), with zero meaning the signals have either no perceivable
>> relation or exact 90-degrees phase relation.
>>
>> If your file includes sine waves of a known frequency, it might be
>> possible to then determine a time delay. If nothing else, a coherence
>> measurement is a useful tool to have at your disposal.
>>
>> David
>> On Mon Mar 2, 2009 9:43 am ((PST)) "s...@worldonline.fr" skeid@worldonline.fr
>> wrote:
>>> Hello all,
>>>
>>> I have at my disposal stereo wave files of binaural recordings, ie
>>> recordings for which the left channel corresponds to the signal
>>> perceived by the left ear, and the right channel to the right ear.
>>>
>>> I have made a small program that compute the rms amplitude of each
>>> channel and takes the ratio, because my recordings have a constant
>>> amplitude I figured it would be close to an Intensity difference...
>>>
>>> But I am starting to have doubts, I don't think it makes sense...
>>>
>>> How would you proceed to calculate these ILDs with just that wave
>>> file?
>>>
>>>
>>> I am quite confused
>>> Thanks for your help
>>>
>>> Nicolas
>
_____________________________________
